(bak´presh-&r) (n.) Also referred to as backpressure flow control, a condition wherein a switch causes a transmitting device to hold off on sending data packets until the switch��s bottleneck has been eliminated (i.e., when its buffers holding data have been emptied). In order to create backpressure, the switch either broadcasts false collision detection signals or sends packets back to the originating device if the buffer is full.